EP2687493A2 - Method for producing a household appliance element and household appliance element - Google Patents

Abstract

The method comprises introducing an optical marker (14a), which is visible only under a special condition. The marker is formed at an external surface of a raw item of a household appliance element (10a). The optical marker is formed by laser handling. A laser light is focused with a radiation intensity of 1 GW/cm 2>. A pulsed laser with pulse duration of 50 ns is used. The laser light has a focus diameter of 30 mu m. The pulsed laser has a pulse repetition frequency of 0.5-20 kHz. A laser focus is relative to the raw item of the household appliance element with a rate of 100-400 mm/seconds. The method comprises introducing an optical marker (14a), which is visible only under a special condition. The marker is formed at an external surface of a raw item of a household appliance element (10a). The optical marker is formed by laser handling. A laser light is focused with a radiation intensity of 1 GW/cm 2>. A pulsed laser with pulse duration of 50 ns is used. The laser light has a focus diameter of 30 mu m. The pulsed laser has a pulse repetition frequency of 0.5-20 kHz. A laser focus is relative to the raw item of the household appliance element in parallel processing lines with a rate of 100-400 mm/seconds and with a line spacing of adjacent lines of 1-200 mu m. An independent claim is included for a household appliance element.

Description

The invention is based on a method for producing a domestic appliance element according to the preamble of claim 1.

From the DE 20 2006 004 064 U1 is a glass-ceramic disc is known in which by means of a pulsed laser which emits light having a wavelength of 532 nm or 1064 nm, characters and / or ornamentation are introduced. A focusing of the light inside the glass-ceramic pane results in the formation of reflection surfaces within the glass-ceramic pane, whereby the characters and / or the ornamentation become visible to a viewer.

The object of the invention is in particular to provide a domestic appliance element with a advantageously extended optical functionality. The object is achieved by the characterizing features of claim 1, while advantageous embodiments and refinements of the invention can be taken from the dependent claims.

The invention is based on a method for producing a domestic appliance element, in particular a hob plate.

It is proposed that in one method step at least one optical marking is introduced, which is at least partially visible at least substantially only under a special condition. A "domestic appliance element" is to be understood in particular as a component of a domestic appliance. Preferably, the domestic appliance element consists at least partially and particularly advantageously to a large extent, in particular with a mass fraction of at least 60%, in particular of at least 70%, preferably of at least 80% and particularly advantageously of at least 90%, of a glass ceramic. In particular, the domestic appliance element can be at least partially optically transparent in a visible wavelength range. In this context, a "hob plate" is intended to be horizontal in particular in an installed position arranged plate element are understood, which is provided in particular for setting up Gargeschirr for Garzwecken. By "provided" is to be understood here and below in particular specially designed and / or equipped and / or programmed. A "marking" is to be understood in particular as meaning a preferably permanent structure in a region of the household appliance element, which may in particular also extend over an entire outer surface of the domestic appliance element, which in particular has a decoration, in particular a linear and / or point-like decoration, and / or or a brand logo and / or brand name. Furthermore, the marking can be embodied as a component identification which is intended to identify and / or track the domestic appliance element, preferably at least partially automated and particularly advantageously fully automated, in particular during transport and / or in a warehouse and / or preferably in a production chain and in particular for an error evaluation and / or for a production and / or storage and / or transport optimization and / or for a quality assurance. The component identification comprises in particular at least one number, in particular a number sequence, and / or at least one bar code and / or at least one 2D code, preferably a DataMatrix code, and / or at least one alphanumeric identifier.

By the fact that the marking is at least partially "at least substantially visible only under a special condition" should be understood in particular that at least a part of the marking and preferably the entire mark under a condition deviating from a standard condition, especially in a disassembled from a domestic appliance Household appliance element, is visible and in particular under the standard condition is at least largely invisible. In this context, a "standard condition" should be understood as meaning, in particular, a direction of illumination and / or viewing of the part of the marking that is at least largely parallel to a normal of a main extension plane of the part of the marking. A "main plane of extension" of an object should in particular be understood to mean a plane which is parallel to a largest side surface of a smallest geometric cuboid which just completely surrounds the object, and in particular runs through the center of the cuboid. A "direction at least largely parallel to a normal of a main extension direction" is to be understood in particular a direction which is at an angle of at most with the normal 20 °, in particular of at most 15 °, preferably of at most 10 ° and particularly advantageously of not more than 5 °. By the fact that at least a part of the mark and preferably the entire mark under the standard condition is "at least largely invisible", it shall be understood in particular that the part of the mark by a healthy eye of a normal sight under the standard condition of an environment of the part of the mark at least is substantially indistinguishable, in particular because under the standard condition there is a relative deviation of an intensity reaching the eye of a scattered and / or reflected and / or emitted light from any point of the part of the mark and an intensity reaching the eye from any point of the environment Part of the mark scattered and / or reflected and / or emitted light for each wavelength of light between 380 nm and 780 nm is at most 10%, in particular at most 5%, preferably at most 1% and more preferably at most 0.1%. Preferably, the special condition by certain lighting conditions, in particular by a number of light sources and / or by their arrangement relative to each other and / or relative to the domestic appliance element and / or by their relative light intensity and / or by a light spectrum of at least one light source, and / or by a defined viewpoint on the home appliance element. Preferably, the mark on the domestic appliance element in the event that it is a component marking in the marking, arranged such that the special condition in an installed position of the domestic appliance element and preferably in a mounted state of the domestic appliance element in the domestic appliance is unsatisfiable. Preferably, the mark on the domestic appliance element in the event that it is a decoration and / or a brand logo and / or brand name, arranged such that the special condition in a mounting position of the domestic appliance element and preferably in a mounted state of the domestic appliance element in the domestic appliance in a particular consideration of the domestic appliance and / or by a specific lighting of the domestic appliance, in particular by an internal illumination of the domestic appliance, preferably during at least one operating state of the domestic appliance, is met.

By such a configuration, a home appliance element can be provided with a advantageously extended optical functionality. In particular, a component identification that does not degrade the overall visual impression of the household appliance element can be created, in particular in the case of one in the visible wavelength range at least partially transparent household appliance element. In particular, an identification and / or follow-up of the domestic appliance element during transport and / or in a warehouse and / or in a production chain can be advantageously optimized, in particular in the case of an at least partially transparent domestic appliance element. Furthermore, advantageously further design options can be opened.

In a preferred embodiment of the invention, it is proposed that the marking is produced on an outer surface of a raw element of the domestic appliance element. An "outer surface" of a component should in particular be understood to mean a touchable surface of the component, in particular in a state disassembled from the domestic appliance. A "raw element" of the domestic appliance element is intended in particular to be understood to mean a component from which the domestic appliance element emerges by the method, in particular by the method step. In this way, a reliability and reproducibility of the method can be ensured. Furthermore, particularly advantageous optical effects can be achieved. In particular, visibility in the special condition can be improved.

In a particularly preferred embodiment of the invention it is proposed that the marking is introduced by means of a laser treatment. A "laser treatment" is to be understood as meaning, in particular, irradiation of at least one area of the household appliance element, with the irradiation in particular inducing a structural change of the area, in particular by a local temperature increase. In this way, an advantageously fast, precise, cost-effective and reproducible introduction of the marking can be made possible. In particular, a non-contact and thus preferably damage and / or contamination and / or contamination-free marking of the household appliance element is possible. Furthermore, an application of the method for almost any material is conceivable, so that in particular a single laser arrangement can be used for introducing markings into different domestic appliance elements. Preferably, a solid-state laser, in particular a diode-pumped solid-state laser and particularly advantageously a Nd: YAG laser is used. As a result, space can be saved and it can be achieved a higher operating reliability. Furthermore, an optical pumping efficiency and a beam quality can advantageously be increased. If the laser has an average power of at least 5 W, in particular of at least 7.5 W and particularly advantageous from has at least 10 W, an advantageous high processing efficiency can be achieved. Preferably, in particular in the case of a household appliance element which consists at least largely of a glass ceramic, the laser treatment is carried out with a laser wavelength between 355 nm and 3000 nm, in particular in the near infrared wavelength range, preferably between 780 nm and 1400 nm and particularly advantageously 1064 nm , Preferably, the domestic appliance element is at least partially transparent for at least one wavelength emitted by the laser. In this way, a particularly advantageous processing of the domestic appliance element can be achieved, since a spatial distribution of an energy deposition can be precisely controlled by a corresponding focusing of a laser light.

Advantageously, laser light is focused with an irradiation intensity of at least 1 GW / cm ² , in particular of at least 10 GW / cm ² , preferably of at least 20 GW / cm ² and particularly advantageously of at least 30 GW / cm ² . By "irradiance" is meant in particular an amount of energy irradiated by the laser per unit time and area. In this way, a sufficiently high energy deposition can be achieved to induce the structural change of the irradiated area of the domestic appliance element. Preferably, focusing takes place on the outer surface of the household appliance element. As a result, in particular in comparison to a focusing of the laser light in an interior of the household appliance element, an overly strong increase in pressure caused by a local temperature increase and, consequently, permanently visible damage and / or marking of the domestic appliance element can advantageously be avoided. If the irradiation intensity is in particular at most 300 GW / cm ² , preferably at most 200 GW / cm ² and particularly advantageously at most 100 GW / cm ² , permanently visible damage and / or marking of the domestic appliance element can be avoided particularly advantageously.

It is further proposed that a pulsed laser with a pulse duration of at most 50 ns, in particular of at most 40 ns, preferably of not more than 30 ns and particularly advantageously of not more than 25 ns is used. In this context, a "pulsed laser" is to be understood as meaning, in particular, a laser which emits an electromagnetic energy in time-separated light pulses having a specific pulse energy and a specific pulse duration. By a "pulse energy" is meant in particular an entire electromagnetic emitted during a pulse Energy to be understood. It is in particular at least 0.25 mJ, preferably at least 0.5 mJ and particularly advantageously at least 0.75 mJ. A "pulse duration" should be understood to mean, in particular, a time duration of a light pulse. In a pulsed laser, the irradiance is given in particular by the pulse energy divided by a product of the pulse duration and a focus area. A "focus area" is to be understood as meaning, in particular, a minimal cross-sectional area of a laser light bundle focused in particular by a laser optics. In particular, the laser beam is focused with a fluence of at least 100 J / cm ² , preferably of at least 300 J / cm ² and more preferably of at least 500 J / cm ² . The "fluence" is given in particular by the pulse energy divided by the focus area. As a result, advantageously a high irradiance can be achieved. Furthermore, an unfavorable cooling of irradiated material by heat conduction during a light pulse can be at least largely prevented.

If laser light is focused on a focus diameter of at most 30 μm, in particular of not more than 25 μm, preferably of not more than 20 μm and particularly advantageously of not more than 15 μm, a high irradiation intensity can be achieved particularly advantageously. A "focus diameter" should in particular be understood to mean a diameter of a largest circle which, just parallel to the focus surface, just fits into the focus area of the laser beam.

In a further embodiment of the invention, it is proposed that a pulsed laser with a pulse repetition frequency between 0.5 kHz and 20 kHz, in particular between 1 kHz and 10 kHz, preferably between 1 kHz and 7.5 kHz, advantageously between 1 kHz and 5 kHz and particularly advantageously used between 2 kHz and 5 kHz. A "pulse repetition frequency" should be understood in particular to be a reciprocal value of a time duration between start times of two successive light pulses. In this way, a high irradiation intensity can be achieved, in particular with high availability of the laser.

When a laser focus relative to a raw element of the domestic appliance element at a speed between 100 mm / s and 400 mm / s, in particular between 150 mm / s and 350 mm / s, preferably between 200 mm / s and 300 mm / s, and particularly advantageously between 225 mm / s and 275 mm / s is moved, can be an advantageous Center point distance between two adjacent laser processing points can be achieved, wherein the center point distance of two adjacent and successively introduced laser processing points calculated in particular from the speed divided by the pulse repetition frequency. A "laser processing point" is to be understood in particular as meaning a spatial region of the household appliance element which has been subjected to a laser irradiation, whereby in particular a structural change has been induced in the region. Preferably, a center-to-center spacing of two adjacent and successively introduced laser processing points is between 50 .mu.m and 200 .mu.m, in particular between 75 .mu.m and 175 .mu.m and particularly advantageously between 100 .mu.m and 150 .mu.m. Advantageously, a center-to-center spacing of at least 50 μm, in particular of at least 75 μm and particularly advantageously of at least 100 μm, is maintained between two adjacent laser processing points, as a result of which crack formation in the domestic appliance element is effectively avoided. The laser processing point preferably has a diameter of less than 100 μm, in particular less than 50 μm and particularly preferably less than 20 μm. As a result, an advantageously low visibility of individual laser processing points can be achieved in a standard condition. In particular, it is conceivable that the domestic appliance element is moved and the laser focus is held stationary. Preferably, however, the laser focus is moved and the household appliance element held stationary, whereby the method can be advantageously simplified.

Advantageously, a laser focus relative to a raw element of the domestic appliance element in parallel processing lines with a line spacing of adjacent processing lines between 50 .mu.m and 200 .mu.m, in particular between 75 .mu.m and 175 .mu.m, preferably between 100 .mu.m and 150 .mu.m and particularly advantageously between 100 .mu.m and 125 .mu.m emotional. In this context, a "processing line" is to be understood as meaning, in particular, a preferably straight connecting line of a subset of laser processing points introduced in chronological succession. Here too, in particular, the domestic appliance element can be moved and the laser focus can be held stationary. Preferably, however, the laser focus is also moved and the household appliance element held stationary. In this way, a sufficiently high distance between adjacent laser processing points can be ensured, whereby damage to the domestic appliance element can be effectively avoided. Furthermore, an advantageous and in particular flat mark can be created.

Furthermore, a domestic appliance element is proposed, which is produced in particular by a method according to the invention and which comprises at least one marking which is at least partially visible at least substantially only under a special condition. The domestic appliance element may in particular be designed as a hob plate of a hob. Preferably, the marker is disposed on an outer surface of the domestic appliance element. In this way, a domestic appliance element can be provided with advantageously extended optical functionality.

Furthermore, a domestic appliance, in particular a hob, with a corresponding domestic appliance element is proposed. In particular, the domestic appliance and / or a further domestic appliance and / or a kitchen furniture can comprise a lighting unit which illuminates the marking in at least one operating state such that the special condition is met. In this way, a domestic appliance can be provided with advantageously extended optical functionality. In particular, a hob can be provided, the hob plate having at least one mark which is illuminated in at least one operating state and at least substantially invisible in a deactivated state of the hob.

Further advantages emerge from the following description of the drawing. In the drawing, two embodiments of the invention are shown. The drawing, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

Fig. 1

ein Hausgerät mit einem Hausgeräteelement, welches durch ein erfindungsgemäßes Verfahren hergestellt ist, in einer Draufsicht,

Fig. 2

das Hausgeräteelement in einer schematischen und nicht maßstabsgetreuen Schnittdarstellung entlang einer Linie II-II in Fig. 1,

Fig. 3

einen Teil des Hausgeräteelements in einer schematischen und nicht maßstabsgetreuen Draufsicht,

Fig. 4

eine schematische und nicht maßstabsgetreue Darstellung eines Verfahrensschritts des Verfahrens zur Herstellung des Hausgeräteelements,

Fig. 5

ein weiteres Hausgerät mit einem alternativen Hausgeräteelement in einer Draufsicht und

Fig. 6

das Hausgeräteelement aus Fig. 5 in einer schematischen und nicht maßstabsgetreuen Schnittdarstellung entlang einer Linie VI-VI in Fig. 5.

Show it:

Fig. 1

a domestic appliance with a domestic appliance element, which is produced by a method according to the invention, in a plan view,

Fig. 2

the domestic appliance element in a schematic and not true to scale sectional view along a line II-II in Fig. 1 .

Fig. 3

a part of the household appliance element in a schematic and not to scale top view,

Fig. 4

a schematic and not to scale representation of a method step of the method for producing the domestic appliance element,

Fig. 5

another household appliance with an alternative home appliance element in a plan view and

Fig. 6

the household appliance element Fig. 5 in a schematic and not to scale sectional view along a line VI-VI in Fig. 5 ,

FIG. 1 shows a trained as a cooktop 36a home appliance 34a with a domestic appliance element 10a which is produced by a method according to the invention, in a plan view. The home appliance element 10a is designed as a cooktop plate 12a. The household appliance element 10a has a main body 38a. The main body 38a is plate-like. The main body 38a consists of a glass ceramic. The glass-ceramic is available under the trade name "Ceran Suprema". The main body 38a is largely opaque and has only partial transparency in the red wavelength range. Heating zones 42a, 44a, 46a, 48a are marked in a known manner on an upper side 40a of the main body 38a. Each of the heating zones 42a, 44a, 46a, 48a is assigned a heating unit (not shown) below the hob plate 12a, each of which preferably has at least one induction heating element. Furthermore, touch-sensitive surfaces of a control unit may be marked on the upper side 40a of the main body 38a (not shown). The household appliance element 10a has a marking 14a, which is at least substantially visible only under a special condition. The marking 14a is introduced on an underside 50a of the main body 38a opposite the upper side 40a of the main body 38a of the domestic appliance element 10a. The mark 14a is a component mark 52a which is provided to identify the home appliance element 10a. The component identifier 52a is embodied as a machine-readable code and, in particular during a production of the domestic appliance 34a, serves to track the domestic appliance element 10a, in particular for purposes of quality assurance.

FIG. 2 shows the domestic appliance element 10a in a schematic and not to scale sectional view along a line II-II in FIG. 1 , FIG. 3 shows a part of the domestic appliance element 10a in an enlarged and schematic plan view of the bottom 50a. The marking 14a consists of a multiplicity of laser processing points 54a introduced into the underside 50a of the main body 38a, of which in the characters 2 and 3 in each case only one is designated. The laser processing points 54a are shown greatly enlarged in the figures to improve their visibility. A diameter 56a of the laser processing points 54a is about 13 μm each. The laser processing points 54a are arranged in mutually parallel processing lines 28a, 30a, of which in FIG. 3 only two are shown by way of example. A line spacing 32 of two adjacent processing lines 28a, 30a is approximately 100 μm in each case. A center distance 58a of immediately adjacent laser processing points 54a of a processing line 28a, 30a is about 125 μm each.

In the special condition under which the mark 14a is visible, it is a certain viewing angle 60a. The marking 14a is only visible if, provided sufficient illumination is available, the marking 14a is viewed from the underside 50a and a viewing angle 60a relative to a normal vector 62a of the underside 50a is between 20 ° and 60 ° (cf. FIG. 2 ). This special condition is met in the production of the household appliance 34a by an automatic reading device of a production line, so that an identification of the domestic appliance element 10a can take place in the production line. On the other hand, the special condition for the domestic appliance element 10a in a state mounted in the domestic appliance 34a is unsatisfactory, since in this case, viewing is only possible from the upper side 40a, so that the required viewing angle 60a is unattainable. Thus, the mark 14a is invisible on the finished home appliance element 10a, although the main body 38a of the domestic appliance element 10a has a certain transparency.

FIG. 4 shows a non-scale and schematic representation of a method step of the method for producing the domestic appliance element 10a. In the method step, the optical marking 14a, which is at least partially visible at least substantially only under a special condition, is introduced. The method step is a laser treatment of a raw element 18a of the domestic appliance element 10a. By the laser treatment, the raw element 18a is transferred into the main body 38a of the domestic appliance element 10a. The laser used is a commercially available "E-Line 20" series laser from ROFIN-SINAR Technologies, Inc. The laser is a diode-pumped solid-state laser. The laser is a diode-pumped Nd: YAG laser. The laser emits laser light 20a of a radiation wavelength of 1064 nm. The laser has a maximum average power of 10 W. The laser is operated pulsed by means of a Q-switch. A Gaussian beam TEM ₀₀ emitted by the laser has a diffraction factor M ² <1.3. The laser is operated with a pulse duration of 22 ns. A pulse energy, ie an electromagnetic energy emitted per pulse, is 0.75 mJ. A pulse peak power is 40 kW. The laser is operated with a pulse repetition frequency of 2 kHz. A laser current is 25 A.

The light emitted from the laser light laser 20a is focused on an outer surface 16a of the Rohelements 18a having an irradiation intensity of about 30 GW / cm ² by means of a not shown, but generally known in the art laser optics unit. The laser light 20a is largely perpendicular to the outer surface 16b. The laser light 20a is focused on the outer surface 16b to a focus diameter 22a of 13 μm. The fluence, ie the energy deposition per pulse and unit area, is approximately 565 J / cm ² . The high irradiance in a laser focus 24a during a pulse leads to evaporation of a material of the raw element 18a. The material in an environment of the laser focus 24a remains substantially unaffected due to the significantly lower irradiance prevailing there. The laser optical unit comprises a lens for a fivefold expansion of the laser light 20a and a convex lens with a focal length of 100 mm, so that the laser light 20a has a Rayleigh length of 95 μm behind the laser optical unit. Furthermore, the laser optical unit has two deflection mirrors, which are controlled by means of a galvanometer by a CAD software. The laser focus 24a is moved relative to the blank 18a at a speed 26a of 250 mm / sec. The pulse repetition frequency of 2 kHz and the speed 26a of 250 mm / s give the center distance 58a between two adjacent laser processing points 54a of 125 μm. As already in FIG. 3 is indicated, the laser focus 24a is guided in processing lines 28a, 30a over the outer surface 16a of the Rohelements 18a. The line spacing 32a of adjacent processing lines 28a, 30a is 100 μm.

By further subsequent method steps, for example a marking of the heating zones 42a, 44a, 46a, 48a on the upper side 40a of the main body, the main body 38a can be transferred into the domestic appliance element 10a.

In the FIGS. 5 and 6 a further embodiment of the invention is shown. The following descriptions are essentially limited to the differences between the embodiments, with respect to the same components, features and functions on the description of the embodiment of FIGS. 1 to 4 can be referenced. To distinguish the embodiments, the letter a in the reference numerals of the embodiment in the FIGS. 1 to 4 by the letter b in the reference numerals of the embodiment of FIGS. 5 and 6 replaced. With regard to identically named components, in particular with regard to components having the same reference symbols, it is also possible in principle to refer to the figures and / or the description of the exemplary embodiment of FIG FIGS. 1 to 4 to get expelled.

FIG. 5 shows a trained as a cooktop 36b home appliance 34b with a household appliance element 10b, which is produced by a method according to the invention, in a plan view. The home appliance element 10b is formed as a cooktop plate 12b. The household appliance element 10b has a main body 38b. The main body 38b is plate-like. The main body 38b consists of a glass ceramic. The glass-ceramic is available under the trade name "Ceran Cleartrans". The main body 38b is transparent. Heating zones 42b, 44b, 46b, 48b are marked in a known manner on an upper side 40b of the main body 38b. Each of the heating zones 42b, 44b, 46b, 48b is assigned a heating unit (not shown) below the hob plate 12b, each of which preferably has at least one induction heating element. Furthermore, touch-sensitive surfaces of a control unit may be marked on the upper side 40b of the main body 38b (not shown).

FIG. 6 shows the domestic appliance element 10b in a schematic and not to scale sectional view along a line VI-VI in FIG. 5 , The household appliance element 10b has a coating 64b, which is arranged on an underside 50b of the main body 38b opposite the upper side 40b. The coating 64b is at least substantially opaque and provided to optically shield structural units of the hob 36b, in particular the heating units, arranged under the hob plate 12b, so that they can no longer be seen from the upper side 40b of the main body 38b. Preferably, the coating 64b is formed as a metallic coating 64b, which imparts a metallic appearance to the domestic appliance element 10b when viewed from the upper side 40b. The home appliance element 10b has a mark 14b, which is at least substantially visible only under a special condition. The marking 14b is introduced at the upper side 40b of the main body 38b. The mark 14b is a brand name 66b. The brand name 66b may be, for example, a brand name and / or a brand logo. The mark 14b is in a direction to the mark 14a of the embodiment of FIGS. 1 to 4 identical way from laser processing points 54b formed.

In the special condition under which the mark 14b is visible, it is a certain lighting condition. The marking 14b is at least substantially visible only when light from the main body 38b passes through the top 40b of the main body 38b to the outside. The hob 36b has for this purpose at least one illumination unit 68b. The illumination unit 68b is arranged on a side surface 70b of the main body 38b. The illumination unit 68b irradiates light laterally into the main body 38b in an operating state of the cooking field 36b, preferably in such a way that the light, as in FIG FIG. 6 schematically indicated by reflections on the upper side 40b and the bottom 50b propagated through the main body 38b. Since the condition of total reflection is no longer met in the region of the marking 14b, the light exits from the base body 38b there, whereby the marking 14b becomes visible. The cooktop 36b thus has a marking 14b which includes a brand name 66b and which is visible and in particular illuminated only in an operating state of the cooktop 36b.

reference numeral 10 Hausgeräte element 62 normal vector 12 Hotplate 64 coating 14 mark 66 brand name 16 Outer surface 68 lighting unit 18 raw element 70 side surface 20 laser light 22 Focus diameter 24 laser focus 26 speed 28 processing line 30 processing line 32 line spacing 34 household appliance 36 hob 38 body 40 top 42 heating zone 44 heating zone 46 heating zone 48 heating zone 50 bottom 52 component labeling 54 Laser processing point 56 diameter 58 Center distance 60 viewing angle

Claims (11)

A method for producing a domestic appliance element (10a, 10b), in particular a cooktop plate (12a, 12b), characterized in that in one method step at least one optical marking (14a, 14b) is introduced, which at least partially at least substantially visible only under a special condition is. Method according to claim 1, characterized in that the marking (14a; 14b) is produced on an outer surface (16a; 16b) of a blank (18a; 18b) of the domestic appliance element (10a; 10b). A method according to claim 1 or 2, characterized in that the marking (14a, 14b) is introduced by means of a laser treatment. A method according to claim 3, characterized in that laser light (20a, 20b) is focused with an irradiance of at least 1 GW / cm ² . A method according to claim 3 or 4, characterized in that a pulsed laser is used with a pulse duration of at most 50 ns. Method according to one of Claims 3 to 5, characterized in that laser light (20a; 20b) is focused onto a focus diameter (22a; 22b) of at most 30 μm. Method according to one of claims 3 to 6, characterized in that a pulsed laser is used with a pulse repetition frequency between 0.5 kHz and 20 kHz. Method according to one of claims 3 to 7, characterized in that a laser focus (24a; 24b) relative to a raw element (18a; 18b) of the domestic appliance element (10a; 10b) at a speed (26a; 26b) between 100 mm / s and 400 mm / s is moved. Method according to one of claims 3 to 8, characterized in that a laser focus (24a, 24b) relative to a raw element (18a, 18b) of the domestic appliance element (10a, 10b) in parallel processing lines (28a, 30a, 28b, 30b) a line spacing (32a, 32b) of adjacent processing lines (28a, 30a, 28b, 30b) is moved between 1 μm and 200 μm. Household appliance element (10a, 10b), in particular hob plate (12a, 12b), which is produced in particular by a method according to one of the preceding claims and which comprises at least one marking (14a, 14b) which at least partially at least substantially only visible under a special condition is. Domestic appliance (34a; 34b), in particular hob (36a; 36b), with a domestic appliance element (10a; 10b) according to claim 10.

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